Flight instruments in the context of Instrument landing system

In aviation, visual flight rules (VFR) is a set of regulations under which a pilot operates an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going. Specifically, the weather must be better than basic VFR weather minima, i.e., in visual meteorological conditions (VMC), as specified in the rules of the relevant aviation authority. The pilot must be able to operate the aircraft with visual reference to the ground, and by visually avoiding obstructions and other aircraft.

If the weather is less than VMC, pilots are required to use instrument flight rules, and operation of the aircraft will be primarily through referencing the instruments rather than visual reference. In a control zone, a VFR flight may obtain a clearance from air traffic control to operate as Special VFR.

A gyrocompass is a type of non-magnetic compass which is based on a fast-spinning disc and the rotation of the Earth (or another planetary body if used elsewhere in the universe) to find geographical direction automatically. A gyrocompass makes use of one of the seven fundamental ways to determine the heading of a vehicle. A gyroscope is an essential component of a gyrocompass, but they are different devices; a gyrocompass is built to use the effect of gyroscopic precession, which is a distinctive aspect of the general gyroscopic effect. Gyrocompasses, such as the fibre optic gyrocompass are widely used to provide a heading for navigation on ships. This is because they have two significant advantages over magnetic compasses:

• they find true north as determined by the axis of the Earth's rotation, which is different from, and navigationally more useful than, magnetic north, and
• they have a greater degree of accuracy because they are unaffected by ferromagnetic materials, such as in a ship's steel hull, which distort the magnetic field.

Aircraft commonly use gyroscopic instruments (but not a gyrocompass) for navigation and attitude monitoring; for details, see flight instruments (specifically the heading indicator) and gyroscopic autopilot.

James Harold Doolittle (December 14, 1896 – September 27, 1993) was an American military general and aviation pioneer who received the Medal of Honor for his raid on Japan during World War II, known as the Doolittle Raid in his honor. He made early coast-to-coast flights and record-breaking speed flights, won many flying races, and helped develop and flight-test instrument flying. According to the FAA, he was the first pilot ever to perform a successful instrument flight.

Doolittle grew up in Nome, Alaska. He attended the University of California, Berkeley, where he graduated with a Bachelor of Arts in 1922. That year, he made the first cross-country flight in an Airco DH.4, and in 1925, was awarded a doctorate in aeronautics from the Massachusetts Institute of Technology, the first such doctorate degree issued in the United States. In 1927, he performed the first outside loop, thought at the time to be a fatal aerobatic maneuver, and two years later, in 1929, pioneered the use of "blind flying", where a pilot relies on flight instruments alone, which later won him the Harmon Trophy and made all-weather airline operations practical.

An attitude and heading reference system (AHRS) consists of sensors on three axes that provide attitude information for aircraft, including roll, pitch, and yaw. These are sometimes referred to as MARG (Magnetic, Angular Rate, and Gravity) sensors and consist of either solid-state or microelectromechanical systems (MEMS) gyroscopes, accelerometers and magnetometers. They are designed to replace traditional mechanical gyroscopic flight instruments.

The main difference between an Inertial measurement unit (IMU) and an AHRS is the addition of an on-board processing system in an AHRS, which provides attitude and heading information. This is in contrast to an IMU, which delivers sensor data to an additional device that computes attitude and heading. With sensor fusion, drift from the gyroscopes integration is compensated for by reference vectors, namely gravity, and the Earth's magnetic field. This results in a drift-free orientation, making an AHRS a more cost effective solution than conventional high-grade IMUs that only integrate gyroscopes and rely on a high bias stability of the gyroscopes.In addition to attitude determination an AHRS may also form part of an inertial navigation system.

In aviation training, a view-limiting device simulates instrument meteorological conditions (IMC) by restricting a pilot's field of view only to the flight instruments. They are worn by pilots who are working toward an instrument rating, which allows a pilot to fly under instrument flight rules in conditions that do not permit visual flight. They are also used by instrument-rated pilots while practicing instrument flight to maintain competency.

Examples include foggles and the IFR hood. Foggles are glasses that have been frosted on the top half of the lenses to simulate foggy conditions.